Conventional loading docks typically include an elevated opening in the side of a warehouse or other building. The opening is generally covered by a door when the loading dock is not in use. To load or unload a trailer or other shipping vehicle, the doors on the back of the trailer are opened and the vehicle is backed up to the loading dock door. Once in position, a vehicle restraint is typically employed to keep the vehicle from inadvertently moving away from the loading dock during the loading and/or unloading process. The loading dock door is then raised, and a dock leveler is extended into the trailer so that workers, forklifts, etc. can transfer cargo into and/or out of the trailer over the dock leveler. Once the loading/unloading process is complete, the dock leveler is retracted and the loading dock door is lowered. The vehicle restraint is then removed so that the trailer can depart the loading dock.
Various types of vehicle restraints are used in the material handling industry to prevent vehicles from moving away from loading docks during loading and/or unloading. Such devices include mechanical restraints that are anchored to the dock face or driveway and include a mechanical hook that can be raised to engage the Rear Impact Guard (“RIG”) bar of the vehicle. Other loading docks employ wheel chocks for vehicle restraint. The use of wheel chocks to block vehicle movement is old and well known in the art. Conventional wheel chocks, for example, have a substantially triangular cross-sectional shape with a curved surface configured to fit against a wheel and prevent movement of the wheel in the direction of the wheel chock. Wheel chock systems are disclosed in U.S. Pat. Nos. 8,590,674, 8,307,956, 8,286,757, 7,864,030, 7,264,092, 7,032,720, and 6,390,245, each of which is incorporated herein by reference in its entirety.
The Smart Chock™ restraint system provided by DL Manufacturing of 340 Gateway Park Drive, North Syracuse, N.Y. 13212, includes a wheel chock having a sensor to detect when the wheel chock has been properly placed in a blocking relationship to the vehicle wheel. The sensor is connected to the loading dock by an electrical cable, so that the sensor can receive power from a loading dock power source and communicate placement signals to a light assembly mounted adjacent to the loading dock. Similar wheel chock systems are described in, for example, U.S. Pat. Nos. 6,336,527, and 7,226,265, and U.S. patent application Ser. No. 10/798,708, each of which is also incorporated herein by reference in its entirety. One shortcoming of these wheel chock systems is that the cable and supporting structure extending between the wheel chock and the loading dock can make placement of the wheel chock cumbersome. Additionally, wear and tear from normal use can lead to frequent service or replacement of the cable and supporting structure. Accordingly, it would be advantageous to provide a wheel chock system that overcame the shortcomings of prior art systems.